General solutions \(W^\mathsf {L}\)  and \(W^\mathsf {R}\)  of (REF ) are given explicitly (cf. for example [1]}) by
\(W^{\mathsf {L}}(z) = H^{\mathsf {L}}(z) z^{\alpha } W_0^{\mathsf {L}},&& W^{\mathsf {R}}(z) =W_0^{\mathsf {R}} (1-z)^{\beta } H^{\mathsf {R}}(z),\) 
